Radio frequency identification aiding the visually impaired with synchronous sound skins

ABSTRACT

Methods, systems, and products for radio frequency identification aiding the visually impaired, storing a recording of a sound, including timing information for synchronous playback, representing at least one attribute of an object having associated with the object a radio frequency identification (“RFID”) tag; activating the RFID tag with an electronic travel aid (“ETA”) for the visually impaired; retrieving the recording from storage; and playing the recording synchronously through an audio interface of the ETA. Storage of sound recording may be local or remote, and sound recordings may be sorted or indexed and retrieved from storage according to an RFID tag identification code, a classification code for the object, and a type code (a sound skin identifier) for the recording.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The field of the invention is data processing, or, more specifically,methods, systems, and products for radio frequency identification aidingthe visually impaired.

2. Description of Related Art

Traditional primary travel aids for the visually impaired include guidedogs and long canes. Secondary aids include such electronic travel aids(“ETAs”) as laser canes and sonar-based devices such as the well-knownSonic Guide™ and Sonic Pathfinder™. All have limitations. One limitationof prior art travel aids is that they provide little or no informationregarding a user's orientation with respect to the general environment.The advent of global positioning systems and cellular telephone networksoffers some hope of delivering to blind users pedestrian informationdescribing location and general environment with accuracy, but costeffective devices for general orientation with blind-friendly displaysare not generally available.

Prior art devices also have limitations regarding orientation withrespect to a local environment and with the detection of hazards notdetected by the use of a primary mobility aid. Long cane users, forexample, find it difficult to maintain a straight travel path withoutsome additional information regarding the local environment. Long caneusers with good hearing may manage straight line travel along the sideof a road carrying traffic and in some cases when walking along a walllistening to the echo of their cane and their foot steps. Some blindcane users may rely on cane contact with the ‘shore’ line or side curb,a cane technique sometimes called ‘touch and drag.’ Guide dog usersoften are almost completely ignorant of the features which border theirroutes. A guide dog is very good at navigating a blind person through alocal environment without contact with or knowledge of the surroundings.

In terms of detection of local obstacles, prior art travel aids for thevisually impaired have limitations. The long cane will not detecthazards above waist height unless the hazards continues down to theground. Sonic-based guides are not good at detecting objects that do notreflect sound well, and some of them are practically useless indoors. Inaddition, it is important to remember that all independent travel isgoal directed. Blind persons must not only avoid things, they must alsofind things. Prior art devices are generally unable to indicate thenature of objects in the environment or the location of objects fartheraway than the length of a cane. For all these reasons, there is adefinite need for improvements in the field of travel aids for thevisually impaired.

SUMMARY OF THE INVENTION

A visually impaired person is empowered to operate an ETA according toembodiments of the present invention to activate RFID tags associatedwith objects in the user's travel environment. The ETA uses data fromthe RFID tag to retrieve sound recordings or audio clips representingobjects, or attributes of objects, in the user's travel environment. Thesound recordings have timing information for synchronous playback.Sounds representing objects may be grouped, by use of sound recordingtype codes or skin identifiers, in related groups called ‘skins.’ Inthis way, a user, upon entering a particular travel environment andusing an ETA to retrieve and play audio clips representing objects inthe environment is presented with a synchronous playback of soundsrepresenting objects in the environment.

ETAs according to embodiments of the present invention typically utilizemulti-channel playback adapters, in some embodiments comprising amultitimbral MIDI synthesizer, in other embodiments a multi-channeldigital audio player, so that a multiplicity of sounds may be playedback at the same time, that is, ‘synchronously,’ thereby providingtiming efficiency with respect to mere serial playback. A user enteringan environment in which sound recordings are grouped, for example, in a‘Sousa’ skin, may be presented with playback of a Sousa march in whichthe trombone part, the trumpet part, and the clarinet part representrespectively the presence in a room of a chair, a sofa, and a hangingplant. Each musical part in this example taken separately represents thepresence of a particular object. The exemplary musical parts, however,are played back synchronously, presenting an apparent playback of apiece of music in which the musical parts are played in correct timewith one another. In this way, a visually impaired user is presentedwith a synchronous display of information regarding a travelenvironment, information presented in a form chosen by the user as apleasant experience for the user. The information presented includesrepresentations of objects at positions in the environment beyond thereach of a long cane and objects whose existence in the environmentwould never be known to the user of a guide dog.

More particularly, methods, systems, and products are disclosed forradio frequency identification aiding the visually impaired that includestoring a recording of a sound representing at least one attribute of anobject having associated with the object a radio frequencyidentification (“RFID”) tag, where the recording includes timinginformation for synchronous playback. Typical embodiments also includeactivating the RFID tag with an electronic travel aid (“ETA”) for thevisually impaired; retrieving the recording from storage; and playingthe recording synchronously through an audio interface of the ETA. Inmany embodiments, playing the recording synchronously includes playingthe recording in accordance with the timing information. Typicalembodiments also include playing a plurality of recordings synchronouslythrough the audio interface of the ETA.

In many embodiments, timing information includes a playback rate andplaying a recording synchronously is carried out by measuring elapsedplayback time and selecting a start time in advance of a current elapsedplayback time. Such embodiments typically also include identifying, independence upon the selected start time and the playback rate, a startpoint in the recording that corresponds to the selected start time, and,when the elapsed playback time matches the selected start time,beginning playback of the recording from the start point.

In many embodiments, storing a recording of a sound includes storing therecording as a MIDI channel number and a MIDI sequence; retrieving therecording from storage is carried out by retrieving the MIDI sequenceand the MIDI channel number; and playing the recording includesinstructing a MIDI sequencer to turn on a MIDI channel identified by theMIDI channel number and sending the MIDI sequence through the sequencerto a multitimbral MIDI synthesizer.

In some embodiments where storing a recording of a sound includesstoring the recording as a MIDI channel number and a MIDI sequence, theembodiments include storing on the RFID tag a classification code forthe object and a type code for the recording. In such embodiments,activating the RFID tag typically includes receiving from the RFID tagin the ETA the classification code for the object and the type code forthe recording. In such embodiments, retrieving the recording fromstorage includes retrieving the MIDI sequence and the MIDI channelnumber in dependence upon the classification code for the object and thetype code for the recording, and playing the recording is carried out byinstructing a MIDI sequencer to turn on a MIDI channel identified by theMIDI channel number and sending the MIDI sequence through the sequencerto a multitimbral MIDI synthesizer.

The other embodiments where storing a recording of a sound includesstoring the recording as a MIDI channel number and a MIDI sequence, theembodiments also include storing on the RFID tag a classification codefor the object and storing in the ETA a type code for the recording. Insuch embodiments, activating the RFID tag includes receiving from theRFID tag in the ETA the classification code for the object; retrievingthe recording from storage includes retrieving the MIDI sequence and theMIDI channel number in dependence upon the classification code for theobject and the type code for the recording; and playing the recording iscarried out by instructing a MIDI sequencer to turn on a MIDI channelidentified by the MIDI channel number and sending the MIDI sequencethrough the sequencer to a multitimbral MIDI synthesizer.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescriptions of exemplary embodiments of the invention as illustrated inthe accompanying drawings wherein like reference numbers generallyrepresent like parts of exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a system for use of an ETA according to embodimentsof the present invention.

FIG. 2 sets forth a line drawing of an exemplary ETA (118) according toembodiments of the present invention.

FIG. 3 is a block diagram of an exemplary ETA showing relations amongcomponents of included automated computing machinery.

FIG. 4 sets forth a flow chart illustrating a method for radio frequencyidentification aiding the visually impaired.

FIG. 5 sets forth a flow chart illustrating a further exemplary methodfor radio frequency identification aiding the visually impaired.

FIG. 6 sets forth a flow chart illustrating a still further exemplarymethod for radio frequency identification aiding the visually impaired.

FIG. 7 sets forth a flow chart illustrating a still further exemplarymethod for radio frequency identification aiding the visually impaired.

FIG. 8 sets forth a flow chart illustrating a still further exemplarymethod for radio frequency identification aiding the visually impaired.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Introduction

The present invention is described to a large extent in thisspecification in terms of methods for radio frequency identificationaiding the visually impaired. Persons skilled in the art, however, willrecognize that any computer system that includes suitable programmingmeans for operating in accordance with the disclosed methods also fallswell within the scope of the present invention. Suitable programmingmeans include any means for directing a computer system to execute thesteps of the method of the invention, including for example, systemscomprised of processing units and arithmetic-logic circuits coupled tocomputer memory, which systems have the capability of storing incomputer memory, which computer memory includes electronic circuitsconfigured to store data and program instructions, programmed steps ofthe method of the invention for execution by a processing unit.

The invention also may be embodied in a computer program product, suchas a diskette or other recording medium, for use with any suitable dataprocessing system. Embodiments of a computer program product may beimplemented by use of any recording medium for machine-readableinformation, including magnetic media, optical media, or other suitablemedia. Persons skilled in the art will immediately recognize that anycomputer system having suitable programming means will be capable ofexecuting the steps of the method of the invention as embodied in aprogram product. Persons skilled in the art will recognize immediatelythat, although most of the exemplary embodiments described in thisspecification are oriented to software installed and executing oncomputer hardware, nevertheless, alternative embodiments implemented asfirmware or as hardware are well within the scope of the presentinvention.

RFID Aiding the Visually Impaired

Exemplary methods, systems, and products for radio frequencyidentification (“RFID”) aiding the visually impaired are now explainedwith reference to the drawings, beginning with FIG. 1. FIG. 1illustrates a system for use of an ETA according to embodiments of thepresent invention. In the example of FIG. 1, recordings (104) of soundsrepresenting attributes of objects having associated with them a radiofrequency identification (“RFID”) tag are stored in storage unit (106).

Sound recordings according to embodiments of the present invention aresometimes referred to in this specification as ‘audio clips.’ Althoughthe use of analog recordings is within the scope of the presentinvention, the sound recordings (104) or audio clips are typicallydigital recordings stored in any digital recording format deemed usefulto those of skill in the art. One example of such a format is ‘WAV,’ thestandard format for use with computers running under the MicrosoftWindows™ operating system. Another example of a digital recording formatis ‘MP3,’ which is an abbreviation of ‘Motion Picture Experts Group,Audio layer 3.’ A further example of a recording format useful for soundrecordings in various embodiments of the present invention is ‘MIDI,’the ‘Musical Instrument Digital Interface.’ Sound recordings accordingto embodiments of the present invention include timing information forsynchronous playback. To the extent that an embodiment utilizes adigital recording format such as WAV or MP3, timing information maycomprise a playback rate, or storing a recording of a sound may includeinserting ‘time stamps’ that identify the time after the beginning ofplayback when parts of such recordings may be played played back, so asto render their playback synchronous. In fact, throughout thisspecification, the term ‘synchronous’ refers to playing sound recordingsin accordance with the timing information. In addition, because visuallyimpaired users will often encounter at the same time multiple objectshaving associated RFID tags that identify recordings representing theobjects, the term ‘synchronous’ also describes playing a plurality ofrecordings synchronously through the audio interface of the ETA, thatis, playing more than one recording simultaneously and synchronously.

As mentioned above, MIDI format is useful according to variousembodiments of the present invention. The MIDI format is useful in thiscontext because the MIDI specification provides a standardized methodfor handing time-stamped MIDI data. The standardized file format fortime-stamped MIDI data allows various applications, such as sequencers,scoring packages, multimedia presentation software, as well as ETAsaccording to the present invention, to share and administer MIDI datasynchronously.

The MIDI standard defines formats for aggregations of MIDI data referredto as ‘files.’ The MIDI standard defines a data communications protocolthat communicates sound playback data to MIDI-enabled devices such assequencers and synthesizers. MIDI data therefore is comprised of asequence of MIDI messages, sometimes stored in files, sometimescommunicated through a data stream, but always including a sequence ofMIDI messages. For this reason, MIDI data is often referred to in thisspecification as a ‘MIDI sequence.’

In a MIDI sequence, timing information for synchronous playback iscommunicated in ‘Timing Clock’ messages. The Timing Clock message is themaster clock that sets the tempo for playback of a MIDI sequence. In theMIDI standard, the Timing Clock messages is sent 24 times per quarternote. To support accurate timing, Timing Clock messages are givenpriority over other messages in a MIDI sequence. Timing Clock messagesmay occur anywhere in MIDI data, even between the bytes comprising othermessage types.

A MIDI sequence is communicated in a single unidirectional bit streamthat is divided into logical channels by the inclusion of a digitallyencoded channel number in many MIDI messages. A musical part istypically recorded on one channel. In the example of the musical partsfor the environment of FIG. 1, the trombones may be recorded on MIDIchannel 1, the clarinets on channel 2, and the trumpets on channel 3.When such a multi-channel MIDI sequence is to be played backsynchronously, it is useful to play the sequence back through amultitimbral synthesizer or sound module. A ‘multitimbral’ synthesizeris capable of playing several different parts simultaneously. A singlemultitimbral sound module or synthesizer, in this example, may beconfigured to receive the trombone part on MIDI channel 1, the clarinetpart on channel 2, and the trumpet part on channel 3.

A MIDI sequencer is a device that is capable of storing, editing,combining, and replaying MIDI data sequences. Output from a MIDIsequencer would typically be connected to the MIDI input of aMIDI-enabled synthesizer, sometimes referred to as a ‘sound generator’or ‘sound module.’ The synthesizer receives a MIDI sequence and respondsto the MIDI messages in the MIDI sequence by playing sounds. In typicalembodiments of ETAs according to the present invention, the controlfunctionality of a sequencer and the sound generation functionality of amultitimbral synthesizer are usefully combined into a singlemulti-channel output interface adapter, referred to in thisspecification as a ‘MIDI adapter.’

In the example of FIG. 1, a visually impaired person (124) uses a longcane (116) as a primary travel aid supplemented by an ETA (118)according to embodiments of the present invention as a secondary travelaid. In this example, the visually impaired person is in a localenvironment (101) that includes a chair (114), a sofa (112), and ahanging plant (110). Such a local environment may be represented by aroom in a residence, a public coffee shop, a reception area in an officebuilding, and many others as will occur to those of skill in the art.

The chair, sofa, and hanging plant each has an RFID device called a‘tag’ associated with it. The chair (114) has an RFID tag (190) embeddedin the seat of the chair. The sofa (112) has an RFID tag (192) embeddedin the upholstery of the sofa. The hanging plant (110) has an RFID tag(110) attached to its container. ETA (118) contains an RFID reader thatcan receive from each RFID tag information that describes the objectwith which the tag is associated.

“RFID” means Radio Frequency Identification, a technology foridentifying objects by use of an antenna, a transceiver, and atransponder or ‘tag.’ RFID transceivers are treated in thisspecification as including the electronic devices needed to convert theinformation in a radio signal into useful computer data; in thisspecification, therefore, RFID transceivers are referred to as “RFIDreaders.” As the term ‘transceiver’ implies, however, RFID readers mayread and write information to and from RFID transponders. RFIDtransponders are referred to in this specification as “RFID tags.” RFIDtags are programmed with RFID identification codes unique to each RFIDtag.

An RFID antenna emits radio signals to activate an RFID tag and read andwrite data to and from the tag. Antennas act as data conduits betweentags and transceivers or RFID readers. Antennas are available in avariety of shapes and sizes. ETA (118) includes a directional antennapackaged with it, built into its case, for portable, handheld use. AnRFID reader in ETA (118) typically emits radio waves at power levels andat frequencies that are useful at ranges of anywhere from a few inchesto 100 feet or more. When an RFID tag (114) passes through theelectromagnetic field of a radio signal from an RFID antenna, the RFIDtag detects the reader's activation signal. The reader decodes the dataencoded in the tag's integrated circuit, typically a silicon chip.

An RFID device that did not actively transmit to a reader wastraditionally known as a ‘tag.’ An RFID device that actively transmittedto a reader was known as a transponder (TRANSmitter+resPONDER). It hasbecome common in the industry, however, to interchange terminology andrefer these devices as either tags or transponders more or lessinterchangeably. In this specification, for clarity of usage, the term‘tag’ is used to refer generally to all RFID devices.

Tags are programmed with data that identifies the tag and therefore theitem or object to which the tag is attached, inserted, embedded, orotherwise associated. Tags can be either read-only, volatile read/write,or write once/read many (“WORM”) and can be either active or passive.Active tags generally use batteries to power the tag's radio transmitterand receiver. Active tags generally contain more components than dopassive tags, so active tags are usually larger in size and moreexpensive than passive tag. An active tag's memory size varies accordingto application requirements; some systems operate with up to a megabyteor more of memory. The useful life of an active tag is related to itsbattery life. Passive tags can be either battery or non-batteryoperated, according to their intended applications.

Passive tags reflect the RF signal transmitted to them from a reader andadd information by modulating the reflected signal to convey identifyingor descriptive information stored in computer memory in the tag. Apassive tag having a battery usually does not use its battery to boostthe energy of the reflected signal. A passive tag typically would use abattery to maintain memory in the tag or power the electronics thatenable the tag to modulate the reflected signal. Passive RFID tags oftenoperate without a battery or other power source, obtaining operatingpower generated from an RFID reader. Passive tags are typically muchlighter than active tags, less expensive, and offer a very longoperational lifetime. The trade off is that passive RFID tags haveshorter read ranges than active tags and require a higher-poweredreader.

RFID tags come in a wide variety of shapes and sizes. Animal trackingtags, inserted beneath an animal's skin, can be as small as a pencillead in diameter and one-half inch in length. Some tags are screw-shapedto identify trees or wooden items, or credit-card shaped for use inaccess applications. The anti-theft hard plastic tags attached tomerchandise in stores are RFID tags.

In the example of FIG. 1, RFID signal (122), transmitted from an RFIDreader in ETA (118), activates RFID tag (190), a small form-factor,passive tag embedded in the seat of chair (114). Tag (190) has stored incomputer memory within it at least one unique identifications code orserial number that uniquely identifies the tag.

More and more manufacturers include RFID tags in manufactured items, forlife cycle monitoring, anti-theft purposes, maintenance aids, and so on.As RFID tags become more common in items of manufacture, a new aid tothe blind may be effected by including in tags in manufactured itemsclassification codes for objects with which the tags are to beassociated or a type code for a sound recording representing anattribute of an object. Predefined sets of classification codes forobjects and type codes for sounds may be predefined by standardsorganizations, so that the same codes are used by many or allmanufacturers. In this way, an ETA according to embodiments of thepresent invention may be manufactured that will work with objects andsound recordings manufactured or provided from any source.

In the example of FIG. 1, ETA (118) contains an RFID reader capable ofreceiving from tag (190) an identification code for the tag, aclassification code for the object (the chair), or a type code for arecording. Upon receiving the identification code for the tag, andoptionally also a classification code for the chair or) or a type codefor a recording, ETA (118) retrieves a recording from storage and playsthe recording through an audio interface of the ETA. The audio interfacemay be multi-channel so as to support playback of more than one audioclip at the same time and may include a speaker or headphones. The audioclips are usefully recorded in the form of MIDI messages inmulti-channel MIDI sequence, where each channel encodes one clip.

Although the sound recordings (104) in the example of FIG. 1 are shownstored in a location that is remote from the ETA and the environment inwhich the ETA is currently operating, that is not a limitation of theinvention. In fact, sound recordings or audio clips, given sufficientmemory, may also be stored in RFID tags or in the ETA itself. One of theadvantages of the MIDI format, in fact, is that a recording in the formof a MIDI sequence is much smaller in terms of memory required forstorage than is the same recording in the form digitized audio such asWAV or MP3. Audio clips may be stored in an ETA in magnetic memory as,for example, a microdrive, in read-only memory (“ROM”), in electricallyerasable programmable read only memory (“EEPROM” or ‘flash memory’), andin other ways as will occur to those of skill in the art. In cases whereonly a single audio clip is stored on an RFID tag embedded in or affixedto an object, then determining which audio clip to play to represent theobject or an attribute of the object is the trivial case: there is onlyone to choose from.

All storage locations for sound recordings, given sufficient memory, arecapable of storing more than one sound recording, therefore presentingthe question which one or more of the recorded clips are to be played atany particular time. Many ETAs according to the present inventiontherefore are programmed to retrieve a particular audio clip fromstorage in dependence upon a classification code for an object withwhich an RFID tag is associated and a type code for sound recordings. Ineffect, the type code for sound recordings typically implements agrouping referred to in this specification as a ‘sound skin.’ Byproviding both an object classification code and a sound recording typecode, ETAs according to the present invention infer that for aparticular object, a particular audio clip is to be played.

If, for example, a sound recording type code identifies a sound skin fornature sounds, and an object classification code identifies an object asa chair, an ETA may retrieve an audio clip of a chirping cricket, thesound recording that represents the presence of a chair in the ‘naturesounds’ sound skin. Change the sound skin, the value of the soundrecoding type code, and the sound recording retrieved and played torepresent the presence of the chair may be a French horn passage from aclassical music skin or a lawn mower noise from a suburban living skin.

The largest store of memory available for storing sound recording may beremote storage on large databases, and recordings from storage thereforeis often carried out, as shown in FIG. 1, by retrieving sound recordingsthrough a network (102) from a remote store (106) of such soundrecordings (104). In the example of FIG. 1, ETA (118) includes awireless communications adapter capable of effecting a datacommunications connection with wireless router (108). A useful aspect ofmobile computing is the fast growing use of wireless routers or wirelessaccess points, sometimes known as ‘hot spots,’ which allow portablecomputer users to function on the move. Hot spots are found now incoffee shops, hotels, lounges, book stores, restaurants, airports, andso on. Wireless router (108) represents such a hot spot, presenting theavailability of convenient data communications to ETA (118) and its user(124).

Although the example of a data communications connection to retrievesound recording remotely is represented in FIG. 1 as a wirelessconnection, in fact, that is not a limitation of the present invention.Wired Internet connections, for example, are available in many publicand private environments such as hotel rooms, offices, and so on, andETA (118) is advantageously and optionally also implemented with a wiredcommunications adapter, such as, for example, an Ethernet adapter, foruse with wired data communications connections.

ETA (118) is programmed to carry out data communications to retrievesound recordings (104) from storage unit (106) by transmitting messagesformulated according to a data communication protocol which may be, forexample, HTTP (HyperText Transport Protocol), WAP (Wireless AccessProtocol), HDTP (Handheld Device Transfer Protocol), or others as willoccur to those of skill in the art. ETA (118) in this examplecommunicates with storage unit (106) through server (103) which providesserver-side functionality for database access in the form of Javaservlets, CGI (Common Gateway Interface) scripts, or other server-sidefacilities for computer resource management as will occur to those ofskill in the art.

Server-side functionality such as a Java servlet or a CGI script forretrieving particular sound recordings (104) are identified by ETA (118)by use of URLs (Uniform Resource Locators) or URIs (Uniform ResourceIdentifiers), and the ETA transmits a data communications protocolmessage to a server-side function identified by such a URL or URIbearing at least one unique identification code encoded as ‘form data.’In the example of FIG. 1, the server-side functionality supported byserver (103) comprises an on-line service for use by ETAs and thevisually impaired. The on-line service is accessed at a cyberspacelocation, that is, a network address, identified by a URL or URI. ThatURL or URI is stored in RAM or non-volatile memory in ETA (118) as asetup parameter for ETA (118) and used by the ETA (118) in its datacommunications functions.

Because memory size in an ETA or RFID is likely to be limited withrespect to remote memory size in cyberspace, it will occur to readers toask how a manufacturer of an ETA or RFID may know which sound recordingsto store. Which objects will a visually impaired user encounter intravel for which an ETA will need a representative sound recording? Inremote storage, in contrast with local storage in an ETA or an RFID,sound recordings may be stored for all objects and for all skins. Thatis, manufacturers may provide database-oriented web sites where apurchaser of an object bearing an embedded RFID tag may log on and storesound recordings representing the object, multiple sound recordings forthe object, one for every known skin type or recording type code. Havinghuge memory resources, it is entirely feasible for such web sites toimplement storage for all sound recordings for all skins for all objectsbearing RFID tags.

In storage in an ETA, however, audio clips clearly cannot be stored forall objects for all skins. Storage in an ETA nevertheless isadvantageous when a developer of an ETA can identify a relativelylimited set of objects that may usefully be tagged as an aid to thevisually impaired. Examples include an ETA developed as a travel aidthrough a museum, a concert hall, an airport or train terminal, forexample. Other examples include any public place where secondary travelaids for the visually impaired are likely to be needed and particularlysuch public places where wireless hot spots are not available.

In the example of FIG. 1, ETA (118) transmits RFID signal (122) throughan antenna (not shown on FIG. 1). In an environment where severalobjects are present with RFID tags, an omni-directional antenna mayactivate more than one RFID tag at the same time, thereby presenting arisk of interference or confusion. ETA (118) therefore preferablyincludes a directional antenna. Implementing an ETA with a directionalantenna also supports inferring an approximate direction to an object independence upon the orientation of the ETA when a description of theobject is displayed. That is, from the user's point of view, the user(124) enters a local environment (101) and sweeps the environmentdirectionally, from left to right, for example, with ETA (118). BecauseETA (118) uses a directional antenna, the RFID tag (194) in the hangingplant, the RFID tag (192) in the sofa, and the RFID (190) tag in therocking chair are each activated in turn as the ETA is pointed at them,thereby causing retrieval and playback of an audio clip representingeach object as the ETA is pointed approximately at each object, therebyproviding also an indication of the approximate direction from the ETAto each object.

The use of a directional antenna provides also the opportunity to inferand display information representing relative distance to an object. AnRFID reader in ETA (118) is capable of transmitting and receiving over alimited range. The size of the range may vary from a few inches to manyfeet, but it does have some limit, a limit quickly learned by a user.Perceiving a playback of a sound recording for an object, thereforealways signals to the user that the object is with the maximum range ofthe RFID reader in the ETA. In addition, ETA (118) infers an approximatedistance to the object in dependence upon a signal strength of an RFIDsignal from the RFID tag associated with the object. ETA (118) containselectronics that recover and measure the relative radio signal strengthof reflected radio signals from RFID tags. The measurement of therelative radio signal strength is represented internally within the ETA(118) as an electronic digital or analog encoding of signal strength.Such an electronic representation of relative signal strength is thenused as an input to an interface adapter such as one or more soundcards, audio amplifiers, or a multi-channel output adapter, to vary theloudness of the sound recording representing the object. The input tosuch an interface adapter may, for example, be represented by a voltagevariable gain control or other electronic means for affecting loudnessof playback of a sound recording.

FIG. 2 sets forth a line drawing of an exemplary ETA (118) according toembodiments of the present invention. Similar in form factor to a remotecontrol for a television set or a VCR, ETA (118) includes an “Activate”button (150) to trigger its internal RFID reader. In many ETAs accordingto the present invention, Activate button (150) is configured to supporta single press and release so as to trigger a single RFID activation ora series of single RFID operations—or to be held down or locked down forcontinuous RFID operation.

ETA (118) includes a directional antenna (186), which in FIG. 2 is shownin the line drawing of ETA (118), but which as a practical matter istypically mounted on a circuit board within ETA (118), mounted within orupon the case of ETA (118), or otherwise mounted as will occur to thoseof skill in the art. ETA (118) includes a headphone jack (156) and aspeaker (152) to support playback of sound recordings representingobjects or attributes of objects associated with RFID tags. ETA (118)includes an optional tactile display, which may be implemented as arefreshable Braille display or a refreshable non-Braille tactiledisplay.

ETA (118) also includes a keypad (131) to support user entry ofinformation or queries. ETA (118) may be programmed, for example, tosupport user entry of queries regarding objects in an environment. Auser looking for a place to sit down in an airport lounge may enter“sitable,” for example. Then when the activate button is pressed, theETA will ignore responses from RFID tags on non-sitable objects anddisplay for the user only retrieved information describing sitableobjects in the local environment, stools at food stands, seats inwaiting areas, and so on. Whether an object is ‘sitable’ or‘non-sitable’ may be indicated in a classification code for the objectstored in an RFID tag associated with the object and retrieved by theETA when the ETA activates the RFID tag.

ETAs according to embodiments of the present invention typicallyinclude, not only RFID readers, but also automated computing machinerydesigned and implemented to operate an RFID reader to activate RFIDtags, process unique identification codes and other informationretrieved from RFID tags through an RFID reader, retrieve recordingsfrom storage, and play sound recordings through an audio interface. FIG.3 is a block diagram of an exemplary ETA showing relations amongcomponents of automated computing machinery comprising the ETA. In theexample of FIG. 3, ETA (118) includes a processor (164), also typicallyreferred to as a central processing unit or ‘CPU.’ The processor may bea microprocessor, a programmable control unit, or any other form ofprocessor useful according to the form factor of a particular ETA aswill occur to those of skill in the art. Other components of ETA (118)are coupled for data transfer to processor (164) through system bus(160).

ETA (118) includes random access memory or ‘RAM’ (166). Applicationprogram implementing inventive methods of the present invention aretypically stored in RAM (166). In addition, application programs,identification codes for RFID tags, classification codes for the objectsassociated with RFID tags, and type codes for sound recordings (skinidentifiers), and other useful information may be stored in RAM (166) orin non-volatile memory (168). Non-volatile memory (168) may beimplemented as a magnetic disk drive such as a micro-drive, an opticaldisk drive, static read only memory (‘ROM’), electrically erasableprogrammable read-only memory space (‘EEPROM’ or ‘flash’ memory), orotherwise as will occur to those of skill in the art.

ETA (118) includes communications adapter (170) implementing datacommunications connections (184) to other computers (162), which may beservers, routers, or networks. Communications adapters implement thehardware level of data communications connections through which ETAs,servers, and routers send data communications directly to one anotherand through networks. Examples of communications adapters include modemsfor wired dial-up connections, Ethernet (IEEE 802.3) adapters for wiredLAN connections, 802.11b adapters for wireless LAN connections, andBluetooth adapters for wireless microLAN connections.

ETA (118) includes an RFID reader (172) coupled to directional antenna(186). Signal strength detector (188) provides a signal whose magnituderepresents the signal strength of a reflected radio signal received froman RFID tag through RFID reader (172). The signal from signal strengthdetector (188) typically is used to drive automated gain controls in I/Ointerface adapter (180) to vary the loudness of playback of soundrecordings representing attributes of objects.

The example ETA (118) of FIG. 3 includes at least one input/outputinterface adapter (180). Input/output interface adapters implementuser-oriented input/output through, for example, software drivers andcomputer hardware for controlling output to display devices (184) suchas audio displays and tactile displays, as well as user input from userinput devices (182) such as ‘Activate’ buttons and keypads. Input/outputadapter (180) preferably includes more than one audio channel, so thatmore then one audio clip may be played through it at the same time.Input/output adapter (180) in FIG. 3 is shown with three such channels,but three is not a limitation of the present invention; output adaptersaccording to embodiments of the present invention may utilize any numberof audio channels. Moreover, although some embodiments, such as thosefor WAV or MP3 clips, may implement physical channels of audioprocessing and amplification, other embodiments, such as those usingMIDI sequences, implement logical audio channels encoded in a singledata stream. As explained above, in many embodiments of ETAs accordingto the present invention, the control functionality of a sequencer andthe sound generation functionality of a multitimbral synthesizer arepreferably combined into a single multi-channel output interface adapter(180), and such an adapter is referred to in this specification as a‘MIDI adapter.’

As shown in FIG. 1, travel environments often include a multiplicity ofobjects having RFID tags. As a user scans such an environment with anETA, several RFID signals from several tags will often be received andprocessed at approximately the same time, that is. It will be a slowexperience for the user, however, to wait for all the audio clips toplay back serially and separately. It is preferable therefore to playback all audio clips simultaneously and synchronously through more thanone audio channel. Such playback may not be literally simultaneousbecause from the point of view of computer speeds, the playback of eachclip may proceed a second or a fraction of second after another clip.From the point of view of the user, however, it would appear that allaudio clips for all the objects having RFID tags in the environmentplay, overlaying one another, at about the same time and so coordinatedas to present a coherent whole, as in the case of a song or musicalpiece with various parts recorded and played back through separatechannels but still having correct overall temporal relations with oneanother.

It is preferable that sound recordings representing objects arerecordings of sounds other than vocal descriptions of objects. It isdifficult to understand several words heard simultaneously. Theyinterfere with one another and confuse perception. It is possible withinthe scope of the present invention that a sound recording representingan object is simply an oral description of the object. A sound recordingrepresenting a chair may be a recording of a voice speaking the word“chair.” In a room like the one shown in FIG. 1, where there is a chair,a sofa, and a hanging plant. As a user scans such a room with an ETA,the user may be presented with overlapping playback of the words“chair,” “sofa,” and “hanging plant,” thereby presenting a jumbled audioimpression that is difficult to understand. Other kinds of sounds arepreferably heard simultaneously, several notes in a musical scaleforming a chord, for example, a song or musical composition, or even thesimultaneous, synchronous presentation of a chirping cricket, a burblingbrook, and leaves rustling in a breeze.

By way of further explanation, FIG. 4 sets forth a flow chartillustrating an exemplary method for radio frequency identificationaiding the visually impaired that includes storing (402) a recording ofa sound (104), including timing information (450) for synchronousplayback, representing at least one attribute of an object havingassociated with it a radio frequency identification (“RFID”) tag (410).A recording of a sound is referred to as a ‘sound recording’ or an‘audio clip.’ In the method of FIG. 4, storing a recording of a soundmay be carried out by storing the recording as a MIDI channel number anda MIDI sequence. The MIDI channel number is needed because more than onesound recording may be stored in a MIDI sequence, one for each availableMIDI channel. Alternatively, the MIDI channel numbers may be assignedunder CPU control from a pool of channel numbers.

A sound recording may represent one or more attributes of an object. Ina trivial case, the existence of a sound recording representing a singleattribute of an object typically represents merely the attribute of theobject's presence in a travel environment of a visually impaired ETAuser. That is, in the trivial case, the mere existence of arepresentative recording means that the represented object is present.

In more complex examples, variations in sounds recorded may representany attribute of any object, color, size, shape, location, and so on. Anobject located in the north end of a hallway may be represented by asingle, steady musical note played on a violin. The same object locatedin the south end of the same hallway may be represented by the same noteon the same instrument played with a trill. The usefulness of aparticular sound skin to a particular user requires some training, butthe potential quantity of information available for presentationregarding the user's travel environment is large.

The method of FIG. 4 also includes activating (404) the RFID tag with anelectronic travel aid (“ETA”) for the visually impaired, retrieving(406) the recording from storage, and playing (408) the recordingsynchronously through an audio interface of the ETA. The purpose ofactivating the RFID tag is to retrieve from it some data describing theobject with which it is associated. In many instances, retrieving datadescribing an object means retrieving a unique identification code forthe tag such as a serial number and using that code, and perhaps otherdata, to locate and retrieve a sound recording from a data store.

FIG. 4A illustrates a method of playing a recording synchronouslythrough an ETA according to embodiments of the present invention. Themethod of FIG. 4A is explained also with reference to FIG. 4B, a linedrawing depicting timing relationships for the method of FIG. 4A. In theexample of FIG. 4 a, the timing information for synchronous playback istaken as a playback rate (471) for a digital recording format such asWAV, MP3, or any other digital format for sound recordings as will occurto those of skill in the art.

Playback rates may be expressed in terms of some quantity of digitaldata per second, such as, for example, bits/second or bytes/second. Theplayback rate is generally equivalent to the sampling rate for recordinga digital sound recording from an analog source. Consider the example ofWAV files. As the digital audio format used in Microsoft WindowS™, WAVfiles allow different sound qualities to be recorded. When converting ananalogue signal to a digital wav file, the sampling frequency with whichsamples are taken and converted into digital form advantageously is atleast twice that of the highest analogue frequency being captured.Samples can be taken at rates from 8,000 Hz to 48000 Hz. The quality ofthe recording varies with the sampling rate and the sample size.

Not all recordings require the same quality. A sampling rate for CDquality playback, for example, is 44.1 KHz, slightly more than doublethe 20 KHz frequency a person can hear. The sampling rate for digitizingvoice for a telephone-quality conversation is 8 KHz, twice the 4 KHzrequired for the full spectrum of the human voice. Sample size alsoaffects quality. Samples can be taken as 8-bit bytes, 16-bit words,24-bit double-words, or even in larger sizes. CD quality is not only asample rate of 44,100 Hz but also a sample size of 16 bits. Someprofessional recording studios use 24-bit samples or even larger samplesizes at sampling rates as high as 48,000 Hz.

The method of FIG. 4A includes measuring (460) elapsed playback time(470) and selecting (462) a start time (472) in advance of a currentelapsed playback time (474 on FIG. 4B). The elapsed playback timetypically is measured with a computer system clock on the ETA. Theelapsed playback time is measured from a time (labeled ‘time zero’ onFIG. 4B) that represents the beginning of overall playback of one ormore synchronized sound recordings as, for example, would be typedtogether within a skin. A current elapsed playback time (474) representsor approximates a time when an RFID is activated by an ETA. The ETAneeds at least some small amount of time to retrieve the recording fromstorage before beginning playback, so that it is useful to select astart time (472) in advance of the current elapsed playback time (474).

The method of FIG. 4A also includes identifying (464), in dependenceupon the selected start time (472) and the playback rate (471), a startpoint (478 on FIG. 4B) in the recording (476 on FIG. 4B) thatcorresponds to the selected start time (472), and, when the elapsedplayback time matches the selected start time (475), beginning (468)playback of the recording from the start point. The method of FIG. 4Aincludes comparing (466) elapsed playback time (470) and the selectedstart time (472), looping (477) on the comparison until elapsed playbacktime ‘matches’ the selected start time.

The term ‘match’ is used as a reminder that the elapsed playback timetypically will not be measured to exactly equal the selected start time.In fact, ‘matching’ will generally be implemented as ‘equal to orgreater than,’ in the sense that the comparison (466) will be consideredto succeed when the elapsed playback time is equal to or later than theselected start time. This is true because measurements by computer clockare typically conducted at intervals that are very, very short comparedto sound recording playback rates. Detecting that elapsed playback timeis equal to or later than the selected start time, measured in themicroseconds or nanoseconds of CPU clock time intervals, gives an ETAplenty of time to begin synchronous playback from the start point (478).

The method of FIG. 4A includes beginning (468) playback of the recordingfrom the start point when the elapsed playback time matches the selectedstart time (475). The start point may be calculated by subtracting timezero from the selected start time and multiplying the playback rate bythe difference. That is, the start point may be calculated bymultiplying the playback rate by the selected start time expressed asthe time elapsed since time zero. For a selected start time 10 secondsafter time zero for a sound recording in the form of a CD quality WAVclip, the start point in the WAV clip for synchronous playback withanother WAV clip whose playback started at time zero, for example, wouldbe 10 seconds multiplied by the 44,100 words/second. This exemplarystart point is located at the 441,000^(th) 16-bit data word in the WAVclip.

Further according to the example of FIG. 4, the recording may beimplemented as a MIDI sequence stored with a channel number for therecording, and retrieving the recording from storage may be carried outby retrieving the MIDI sequence and the MIDI channel number.Alternatively, the channel number may be assigned from a pool of channelnumbers. Also according to the method of FIG. 4, playing the recordingsynchronously may be carried out by instructing a MIDI sequencer to turnon a MIDI channel identified by the MIDI channel number and sending theMIDI sequence through the sequencer to a multitimbral MIDI synthesizerin the ETA. In the exemplary ETA of FIG. 3, such an instruction isimplemented in an application program in RAM (166) and communicated to aMIDI sequencer of MIDI adapter (180) from processor (164) through systembus (160).

In a trivial case, shown on FIG. 4, storing (402) a recording (104) iscarried out by storing a recording on the RFID tag (410) itself, so thatretrieving (406) the recording is carried out by receiving the recordingin the ETA from the RFID tag when the RFID tag is activated. That is, inthe simple case, retrieving descriptive data means directly receivingright in the ETA, directly from an RFID tag associated with an object, asound recording representing the object or attributes of the object.

In such a case, there is no need for the ETA to know a uniqueidentification code or serial number for the RFID tag, although theinformation retrieved from the tag may sometimes usefully include a typecode for the recording, that is, a skin identifier. Consider an examplein which a skin is identified for use in an ETA through the use of arecording type code or ‘skin identifier’ installed in the ETA as a setupparameter. Such a setup parameter may, for example, be entered throughkeypad such as the one illustrated at reference (131) on FIG. 2 andstored in non-volatile computer memory in the ETA, memory such as thatillustrated at reference (168) on FIG. 3. Such a recording type code orskin identifier represents the user's preferred skin, the user'spreferred grouping of sound recordings representing objects that theuser encounters in travel.

In the current example, in order to support the user's choice of skin,an RFID tag may have recorded upon it a multiplicity of soundrecordings, each of which is identified with a separate recording typecode or skin identifier. In this example, when a user activates such anRFID tag, the activating ETA is programmed to retrieve and playback forthe user only one of the several sound recordings installed on the RFIDtag, the one identified with the same skin identifier installed in thesetup parameters of the ETA. In this way, although the methodology doesrequire rather more memory capacity on the RFID tags, embodiments of thepresent invention nevertheless may support multiple skins with no needfor remote storage or on-line services for remote retrieval of soundrecordings.

FIG. 5 sets forth a flow chart illustrating a further exemplary methodfor radio frequency identification aiding the visually impaired wherestoring (402) a recording (104) is carried out by storing the recording,including timing information (450) for synchronous playback, on an ETA(414). In the method of FIG. 5, storing a recording of a sound may becarried out by storing the recording as a MIDI channel number and a MIDIsequence. The MIDI channel number is needed because more than one soundrecording may be stored in a MIDI sequence, one for each available MIDIchannel.

In the method of FIG. 5, rather than receiving an audio clip from thetag, activating (404) the RFID tag includes receiving (411) in the ETAfrom the RFID tag (410) an identification code (412) for the tag. In themethod of FIG. 5, therefore, retrieving (406) the recording is carriedout by retrieving the recording (104) from storage. In the example ofFIG. 5, retrieval from storage is retrieval from storage in the ETA(414) in dependence upon the identification code for the tag. Retrievalis carried out on dependence upon the identification code for the tagbecause a multiplicity of audio clips may be stored in the ETA, indexedor sorted according to RFID tag identification codes.

In the method of FIG. 5, the recording may be a MIDI sequence storedwith a channel number for the recording, and retrieving the recordingfrom storage may be carried out by retrieving the MIDI sequence and theMIDI channel number, both sorted or indexed according to the tagidentification code or serial number. Also according to the method ofFIG. 4, playing the recording synchronously may be carried out byinstructing a MIDI sequencer to turn on a MIDI channel identified by theMIDI channel number and sending the MIDI sequence through the sequencerto a multitimbral MIDI synthesizer in the ETA. As mentioned above, interms of the exemplary ETA of FIG. 3, such an instruction is implementedin an application program in RAM (166) and communicated to a MIDIsequencer of MIDI adapter (180) from processor (164) through system bus(160).

Memory capacity in an ETA will always be limited, always smaller thanthe memory capacity available through the use of remote storage.Nevertheless, such embodiments are useful in circumstances in which adeveloper or manufacturer can identify a limited range of objects to bedescribed. An example of such a circumstance is any public placefrequented by the visually impaired, particularly places where wirelesshot spots may not be available, places like airports, bus stations,train stations, theatres, libraries, and so on, as will occur those ofskill in the art. In many such environments, managers or ownersadvantageously may make ETAs according to the present inventionavailable to the visually impaired for use during visits to such venues.

FIG. 6 sets forth a flow chart illustrating a still further exemplarymethod for radio frequency identification aiding the visually impairedwhere storing (402) a recording (104) is carried out by storing therecording, including timing information (450) for synchronous playback,in a remote location (106), that is, a location remote from the ETA orremote from the local environment in which the ETA is presentlydeployed. In the method of FIG. 6, storing a recording of a sound may becarried out by storing the recording as a MIDI channel number and a MIDIsequence. The MIDI channel number is needed because, as noted above,more than one sound recording may be stored in a MIDI sequence, one foreach available MIDI channel.

In the method of FIG. 6, activating (404) the RFID tag includesreceiving (411) in the ETA from the RFID tag an identification code(412) for the tag. In the method of FIG. 6, retrieving (406) therecording includes retrieving the recording from the remote location independence upon the identification code for the tag. In the example ofFIG. 6, the retrieval is accomplished remotely across network (102).Readers will appreciate that the method of FIG. 6 is a more generalcase. The identification code (412) for the RFID tag may be associatedwith any object, and its representative sound recording may be locatedanywhere in the world, anywhere in cyberspace.

In the method of FIG. 6, the recording may be a MIDI sequence storedwith a channel number for the recording, and retrieving the recordingfrom storage is preferably carried out by retrieving the MIDI sequenceand the MIDI channel number, both sorted or indexed according to the tagidentification code or serial number. Also in the method of FIG. 4,playing the recording synchronously may be carried out by instructing aMIDI sequencer to turn on a MIDI channel identified by the MIDI channelnumber and sending the MIDI sequence through the sequencer to amultitimbral MIDI synthesizer in the ETA. As mentioned above, in termsof the exemplary ETA of FIG. 3, such an instruction is implemented in anapplication program in RAM (166) and communicated to a MIDI sequencer ofMIDI adapter (180) from processor (164) through system bus (160).

FIG. 7 sets forth a flow chart illustrating a still further exemplarymethod for radio frequency identification aiding the visually impairedwhere storing (402) a recording (104) is carried out by storing therecording, including timing information (450) for synchronous playback,in a remote location. In the method of FIG. 7, storing a recording of asound may be carried out by storing the recording as a MIDI channelnumber and a MIDI sequence. The MIDI channel number is needed because,as noted above, more than one sound recording may be stored in a MIDIsequence, one for each available MIDI channel.

The method of FIG. 7 includes storing (420) on the RFID tag (410) aclassification code (416) for the object and a type code (418) for therecording. In the method of FIG. 7, activating (404) the RFID tagincludes receiving from the RFID tag in the ETA the classification code(416) for the object and the type code (418) for the recording. In themethod of FIG. 7, retrieving (406) the recording (104) from storage iscarried out by retrieving the recording from the remote location independence upon the classification code for the object and the type codefor the recording.

Table 1 illustrates an exemplary data structure useful in storing andretrieving audio clips with methods of the kind shown in FIGS. 7 and 8.TABLE 1 Recording Object Type Code File Classification (Skin System MIDICode Identifier) BLOB Location Channel — — — — — — — — — — — — — — —

For the example of MIDI, the object classification code and therecording type code (skin identifier) of Table 1, taken together,uniquely key a MIDI sequence. To the extent that storage of the MIDIsequence is administered through a database management system thatsupports BLOBs (Binary Large OBjects), each MIDI sequence may be storedin a BLOB field in a record of a table similar to Table 1. For storageunder database management systems that do not support BLOBs, such a datastructure may provide a ‘File System Location’ field that identifieswhere on a file system available to the database manager a MIDI sequenceis stored.

Because each MIDI sequence may contain more than one sound recording onmore than one MIDI channel, in order to uniquely key a particular soundrecording, Table 1 provides a ‘MIDI Channel’ field. In the structure ofTable 1, therefore, the object classification code, the recording typecode, and the MIDI channel number taken together uniquely key not only aparticular MIDI sequence, but also uniquely key a particular soundrecording on a particular channel of the MIDI sequence.

In the method of FIG. 7, where the recording may be a MIDI sequencestored with a channel number for the recording, retrieving the recordingfrom storage may be carried out by retrieving the MIDI sequence and theMIDI channel number, both sorted or indexed according to the objectclassification code and the recording type code (skin identifier). Alsoin the method of FIG. 4, playing the recording synchronoulsy may becarried out by instructing a MIDI sequencer to turn on a MIDI channelidentified by the MIDI channel number and sending the MIDI sequencethrough the sequencer to a multitimbral MIDI synthesizer in the ETA. Asmentioned above, in terms of the exemplary ETA of FIG. 3, such aninstruction is implemented in an application program in RAM (166) andcommunicated to a MIDI sequencer of MIDI adapter (180) from processor(164) through system bus (160).

The method of FIG. 7, in which both the object classification code andthe recording type code (skin identifier) are stored on the RFID tag,may provide users little opportunity or flexibility to alter the skin.It may be easy for tag manufacturers or object manufacturers to alterthe skin identifier in the RFID tag during manufacturing operations, butordinary users may not have the equipment to make such alterations inRFID tags. FIG. 8 illustrates a method in which users are provided moreflexibility regarding skin selection.

FIG. 8 sets forth a flow chart illustrating a still further exemplarymethod for radio frequency identification aiding the visually impairedwhere storing (402) a recording (104) is carried out by storing arecording, including timing information (450) for synchronous playback,in a remote location. In the method of FIG. 8, storing a recording of asound may be carried out by storing the recording as a MIDI channelnumber and a MIDI sequence. As noted above, the MIDI channel number isneeded because more than one sound recording may be stored in a MIDIsequence, one for each available MIDI channel.

The method of FIG. 8 also includes storing (420) on the RFID tag (410) aclassification code (416) for the object. The method of FIG. 8 alsoincludes storing (420) in the ETA a type code (418) for the recording.In the method of FIG. 8, activating (404) the RFID tag includesreceiving (411) from the RFID tag in the ETA the classification code(416) for the object. In the method of FIG. 8, retrieving (406) therecording (104) from storage is accomplished by retrieving the recordingfrom the remote location in dependence upon the classification code forthe object and the type code for the recording.

In the method of FIG. 8, where the recording may be a MIDI sequencestored with a channel number for the recording, retrieving the recordingfrom storage may be carried out by retrieving the MIDI sequence and theMIDI channel number, both sorted or indexed according to the objectclassification code and the recording type code (skin identifier). Alsoin the method of FIG. 4, playing the recording synchronously may becarried out by instructing a MIDI sequencer to turn on a MIDI channelidentified by the MIDI channel number and sending the MIDI sequencethrough the sequencer to a multitimbral MIDI synthesizer in the ETA. Asmentioned above, in terms of the exemplary ETA of FIG. 3, such aninstruction is implemented in an application program in RAM (166) andcommunicated to a MIDI sequencer of MIDI adapter (180) from processor(164) through system bus (160).

In the method of FIG. 8, where the recording type code is stored on theETA, the recording type code is stored in non-volatile memory (168 onFIG. 3) as a setup parameter of the ETA. In this method, the recordingtype code may be altered at any time by the user by, for example, typingin a new recording type code (skin identifier) by use of keypad such asthe one shown at reference (131) on FIG. 2. In this method, a user canvary at will the sound groupings representing object encountered intravel with an ETA.

Readers can now appreciate that the use by visually impaired persons ofETAs according to embodiments of the present invention has substantialadvantages. ETAs according to the present invention can offer a user alarge amount of information regarding the user's general orientation toa travel environment. In addition, the information provided can bevoluminous, precise, and audibly pleasing. Moreover, ETAs according tothe present invention have the capability of describing generally andpleasingly hazards and other objects that would not be detected at allby long canes and would never be known to the user of a guide dog.

It will be understood from the foregoing description that modificationsand changes may be made in various embodiments of the present inventionwithout departing from its true spirit. The descriptions in thisspecification are for purposes of illustration only and are not to beconstrued in a limiting sense. The scope of the present invention islimited only by the language of the following claims.

1. A method for radio frequency identification aiding the visuallyimpaired, the method comprising: storing a recording of a soundrepresenting at least one attribute of an object having associated withthe object a radio frequency identification (“RFID”) tag, wherein therecording includes timing information for synchronous playback;activating the RFID tag with an electronic travel aid (“ETA”) for thevisually impaired; retrieving the recording from storage; and playingthe recording synchronously through an audio interface of the ETA. 2.The method of claim 1 further comprising playing a plurality ofrecordings synchronously through the audio interface of the ETA.
 3. Themethod of claim 1 wherein the timing information comprises a playbackrate and playing the recording synchronously further comprises:measuring elapsed playback time; selecting a start time in advance of acurrent elapsed playback time; identifying, in dependence upon theselected start time and the playback rate, a start point in therecording that corresponds to the selected start time; and when theelapsed playback time matches the selected start time, beginningplayback of the recording from the start point.
 4. The method of claim 1wherein: storing a recording of a sound comprises storing the recordingas a MIDI sequence; retrieving the recording from storage comprisesretrieving the MIDI sequence; and playing the recording synchronouslycomprises instructing a MIDI sequencer to turn on a MIDI channel andsending the MIDI sequence through the sequencer to a multitimbral MIDIsynthesizer.
 5. The method of claim 1 wherein: storing a recording of asound comprises storing the recording as a MIDI sequence; the methodfurther comprises storing on the RFID tag a classification code for theobject and a type code for the recording; activating the RFID tagcomprises receiving from the RFID tag in the ETA the classification codefor the object and the type code for the recording; retrieving therecording from storage comprises retrieving the MIDI sequence independence upon the classification code for the object and the type codefor the recording; and playing the recording synchronously comprisesinstructing a MIDI sequencer to turn on a MIDI channel and sending theMIDI sequence through the sequencer to a multitimbral MIDI synthesizer.6. The method of claim 1 wherein: storing a recording of a soundcomprises storing the recording as a MIDI sequence; the method furthercomprises storing on the RFID tag a classification code for the object;the method further comprises storing in the ETA a type code for therecording; activating the RFID tag comprises receiving from the RFID tagin the ETA the classification code for the object; retrieving therecording from storage comprises retrieving the MIDI sequence independence upon the classification code for the object and the type codefor the recording; and playing the recording synchronously comprisesinstructing a MIDI sequencer to turn on a MIDI channel and sending theMIDI sequence through the sequencer to a multitimbral MIDI synthesizer.7. A system for radio frequency identification aiding the visuallyimpaired, the system comprising: means for storing a recording of asound representing at least one attribute of an object having associatedwith the object a radio frequency identification (“RFID”) tag, whereinthe recording includes timing information for synchronous playback;means for activating the RFID tag with an electronic travel aid (“ETA”)for the visually impaired; means for retrieving the recording fromstorage; and means for playing the recording synchronously through anaudio interface of the ETA.
 8. The system of claim 7 further comprisingmeans for playing a plurality of recordings synchronously through theaudio interface of the ETA.
 9. The system of claim 7 wherein the timinginformation comprises a playback rate and means for playing therecording synchronously further comprises: means for measuring elapsedplayback time; means for selecting a start time in advance of a currentelapsed playback time; means for identifying, in dependence upon theselected start time and the playback rate, a start point in therecording that corresponds to the selected start time; and means forbeginning playback of the recording from the start point when theelapsed playback time matches the selected start time.
 10. The system ofclaim 7 wherein: means for storing a recording of a sound comprisesmeans for storing the recording as a MIDI sequence; means for retrievingthe recording from storage comprises means for retrieving the MIDIsequence; and means for playing the recording synchronously comprisesmeans for instructing a MIDI sequencer to turn on a MIDI channel andmeans for sending the MIDI sequence through the sequencer to amultitimbral MIDI synthesizer.
 11. The system of claim 7 wherein: meansfor storing a recording of a sound comprises means for storing therecording as a MIDI sequence; the system further comprises means forstoring on the RFID tag a classification code for the object and a typecode for the recording; means for activating the RFID tag comprisesmeans for receiving from the RFID tag in the ETA the classification codefor the object and the type code for the recording; means for retrievingthe recording from storage comprises means for retrieving the MIDIsequence in dependence upon the classification code for the object andthe type code for the recording; and means for playing the recordingsynchronously comprises means for instructing a MIDI sequencer to turnon a MIDI channel and means for sending the MIDI sequence through thesequencer to a multitimbral MIDI synthesizer.
 12. The system of claim 7wherein: means for storing a recording of a sound comprises means forstoring the recording as a MIDI sequence; the system further comprisesmeans for storing on the RFID tag a classification code for the object;the system further comprises means for storing in the ETA a type codefor the recording; means for activating the RFID tag comprises means forreceiving from the RFID tag in the ETA the classification code for theobject; means for retrieving the recording from storage comprises meansfor retrieving the MIDI sequence in dependence upon the classificationcode for the object and the type code for the recording; and means forplaying the recording synchronously comprises means for instructing aMIDI sequencer to turn on a MIDI channel and means for sending the MIDIsequence through the sequencer to a multitimbral MIDI synthesizer.
 13. Acomputer program product for radio frequency identification aiding thevisually impaired, the computer program product comprising: a recordingmedium; means, recorded on the recording medium, for storing a recordingof a sound representing at least one attribute of an object havingassociated with the object a radio frequency identification (“RFID”)tag, wherein the recording includes timing information for synchronousplayback; means, recorded on the recording medium, for activating theRFID tag with an electronic travel aid (“ETA”) for the visuallyimpaired; means, recorded on the recording medium, for retrieving therecording from storage; and means, recorded on the recording medium, forplaying the recording synchronously through an audio interface of theETA.
 14. The computer program product of claim 7 further comprisingmeans, recorded on the recording medium, for playing a plurality ofrecordings synchronously through the audio interface of the ETA.
 15. Thecomputer program product of claim 13 wherein the timing informationcomprises a playback rate and means for playing the recordingsynchronously further comprises: means for, recorded on the recordingmedium, for measuring elapsed playback time; means for, recorded on therecording medium, for selecting a start time in advance of a currentelapsed playback time; means for, recorded on the recording medium, foridentifying, in dependence upon the selected start time and the playbackrate, a start point in the recording that corresponds to the selectedstart time; and means for, recorded on the recording medium, forbeginning playback of the recording from the start point when theelapsed playback time matches the selected start time.
 16. The computerprogram product of claim 13 wherein: means for storing a recording of asound comprises means, recorded on the recording medium, for storing therecording as a MIDI sequence; means for retrieving the recording fromstorage comprises means, recorded on the recording medium, forretrieving the MIDI sequence; and means for playing the recordingsynchronously comprises means, recorded on the recording medium, forinstructing a MIDI sequencer to turn on a MIDI channel and means,recorded on the recording medium, for sending the MIDI sequence throughthe sequencer to a multitimbral MIDI synthesizer.
 17. The computerprogram product of claim 13 wherein: means for storing a recording of asound comprises means, recorded on the recording medium, for storing therecording as a MIDI sequence; the computer program product furthercomprises means, recorded on the recording medium, for storing on theRFID tag a classification code for the object and a type code for therecording; means for activating the RFID tag comprises means, recordedon the recording medium, for receiving from the RFID tag in the ETA theclassification code for the object and the type code for the recording;means for retrieving the recording from storage comprises means,recorded on the recording medium, for retrieving the MIDI sequence independence upon the classification code for the object and the type codefor the recording; and means for playing the recording synchronouslycomprises means, recorded on the recording medium, for instructing aMIDI sequencer to turn on a MIDI channel and means, recorded on therecording medium, for sending the MIDI sequence through the sequencer toa multitimbral MIDI synthesizer.
 18. The computer program product ofclaim 13 wherein: means for storing a recording of a sound comprisesmeans, recorded on the recording medium, for storing the recording as aMIDI sequence; the computer program product further comprises means,recorded on the recording medium, for storing on the RFID tag aclassification code for the object; the computer program product furthercomprises means, recorded on the recording medium, for storing in theETA a type code for the recording; means for activating the RFID tagcomprises means, recorded on the recording medium, for receiving fromthe RFID tag in the ETA the classification code for the object; meansfor retrieving the recording from storage comprises means, recorded onthe recording medium, for retrieving the MIDI sequence in dependenceupon the classification code for the object and the type code for therecording; and means for playing the recording synchronously comprisesmeans, recorded on the recording medium, for instructing a MIDIsequencer to turn on a MIDI channel and means, recorded on the recordingmedium, for sending the MIDI sequence through the sequencer to amultitimbral MIDI synthesizer.